1. Field of the Invention
The present invention is related to a device for the adjustment of a temperature of a liquid and a corresponding method.
2. Description of Related Art
It is generally known that chemical analysis of samples and chemical/physical processes must be performed at a predetermined temperature in order to obtain accurate results. In particular for a high number of chemical analysis within a relatively short period of time, or for processes in which a temperature or different temperatures must be adjusted, powerful and cost intensive temperature adjustment units are required in order that these demands can be met.
Different devices and methods for the adjustment of the temperature are known. It is referred representatively to the following documents: DE-42 03 202 A1, EP-0 160 282 B1, EP-0 318 255 A2, WO 98/38487, U.S. Pat. No. 6,210,882 und EP-0 345 882 A1.
The known teachings can basically be divided in two groups. The so-called solid body incubators belong to the first group, for which the samples are heated or cooled by the solid body, for which a corresponding amount of time is needed depending on the heat capacity. If the temperature of liquid samples must be adjusted, one ore more of the following problems occur:                Large thermal masses must also be heated or cooled for a temperature change;        Diffusion limitations occur between a heated sample vessel wall and the liquid (boundary layer creation);        A direct contact between the heat source and the heat sink, respectively, and the sample vessels to be heated is required; a bad contacting between temperature adjustment unit and sample vessel results in a considerable delay for the temperature adjustment;        Contacting by sensor cables act as heat sinks and result in additional losses.        
Temperature adjustment units which are based on a radiation, in particular on an IR-(infrared)-radiation, belong to the second group. An improved behavior can indeed be confirmed compared to the first group but also for this second group a number of disadvantages to be taken into account occur, which disadvantages result in a suboptimal heating behavior for liquids:                Non optimized absorption spectra of the reaction compounds to be heated;        Non optimized transmission spectra of the sample vessels;        Other system elements are unintentionally heated by the IR-radiation.        